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0-1000 psi pressure sensor needed

Catwell
I need a cheap pressure sensor capable of going from 0-1000 psi to measure various compressed gases. Most I have found were well over $100 USD. There must be some alternatives out there.
 
Cabe
  • 0
    Hi Cabe,
    An analog pressure meter using a bourdon tube gauge is cheaper than an electronic one.
    These meters are second hand available for very low prizes.
    Look what I found in a few seconds on the internet.
    image
    They are used for several applications, like diving equipment and gas containers.
    When a pressure meter is not accurate anymore, it is often discarded.
    The accuracy problem could be caused by wear or by dirt on the mechanism between the bourdon tube and the needle.
    You can get such a meter for free from the trash container of a place where maintenance is performed on diving equipment.
    The accuracy problem could be caused by dirt or a worn out mechanism between the bourdon tube and the needle.
    If you want an electronic readout, you could replace the needle by a disk with a print on it that can be read with a ray of light.
    Another way is attaching a pressure sensitive resistor directly to the  bourdon tube. This way you could use an old meter with a worn out mechanism. The picture below shows the inside of a bourdon tube gauge.
    image
  • 0 in reply to jvdberg@ieee.org

    Johan,

     

    Good suggestion, I use something like that right now. But I am looking for a digital solution.

     

    Cabe

  • 0 in reply to Catwell

    These devices are all over the place.

     

    http://images.grainger.com/B341_22/images/products/250x250/Pressure-Transducer-5DEK0_AS01.JPG

     

    Grainger.com about $200.

     

    If you don't need precision and tested calibration, but want to work it out yourself, any cheapo piezo crystal buzzer will deform proportionate to pressure.  For lower values can try a cheapo digital tire gauge and mod it as a pressure sensor far above its rating. Often the sensors can detect much higher than 200 psi,  just its out of range for the devices uC code.

  • 0

    Hi Cabe,

    Perhaps you could roll your own sensor.

    The Bourdon tube mentioned by Johan converts pressure to motion/position but could also be used to convert pressure to force. So you could measure either the position of the Bourdon tube or the force it exerts using some other low-cost sensor. For example you could measure the position with a variable (low friction) capacitor or even an optical sensor, or you could measure the force with a Flexiforce sensor.

    Doug

  • 0 in reply to dougw

    Douglas,

     

    Again... 3 years later!

     

    I will have to look into this FlexForce sensor. http://www.tekscan.com/flexible-force-sensors

    To see is I can put one into a pressure chamber.

     

    Otherwise, there is no way I am going to "roll my own." I would have to potentially make thousands.

     

    Thanks for the thoughts.

     

    C